Tires getting hot

[Beau388]

Tire science - Tires are round except where they touch the pavement (contact patch). Less pressure more of the tire is flat . Remember it is the air in the tire that holds the coach up and the tire is just a vessel to hold the air. Tires heat up because they flex, remember flat on the bottom. The faster you go the more they flex (over a given time period) and heat up. The lower the air pressure the more tires flex and more heat. Cornering causes more tire flex than going straight and more temperature. More weight on the tire the more flex and more heat. Climbing a grade cause the driving tires to heat up (more flex). Back pavement is hotter than white in the sun. Tires shed temperature by contact (conduction) with a surface and by air passing over them (convection). Maximum traction on a treadled tire is at temperatures of 180 F to 200 F degrees. Sooo - if you have plenty of air in your tires (hopefully you have weighed you coach and know what your individual wheel loading is), don't worry UNLESS their is a sudden DROP in tire pressure. For my little 18,000 lb coach, here is what I observe on a 80 degree day on asphalt (all tires set at 85 psi cold) - fronts 16 psi rise in the fronts + 2 psi more in the full sun - rear outside 22 psi rise + 2 degrees in the sun - rear inside 24 psi rise in pressure - all this at 60 mph on a flat Texas Interstate. If you don't like the tire pressure rise amount, add more tire pressure to a cold tire, BUT never exceed the max rated tire pressure on the sidewall (cold tire). - Or you could slow down or reduce weight.
Now I will step down from my soap box.... Next!

[Pete'sMH]

Originally Posted by Beau388

Tire science - Tires are round except where they touch the pavement (contact patch). Less pressure more of the tire is flat . Remember it is the air in the tire that holds the coach up and the tire is just a vessel to hold the air. Tires heat up because they flex, remember flat on the bottom. The faster you go the more they flex (over a given time period) and heat up. The lower the air pressure the more tires flex and more heat. Cornering causes more tire flex than going straight and more temperature. More weight on the tire the more flex and more heat. Climbing a grade cause the driving tires to heat up (more flex). Back pavement is hotter than white in the sun. Tires shed temperature by contact (conduction) with a surface and by air passing over them (convection). Maximum traction on a treadled tire is at temperatures of 180 F to 200 F degrees. Sooo - if you have plenty of air in your tires (hopefully you have weighed you coach and know what your individual wheel loading is), don't worry UNLESS their is a sudden DROP in tire pressure. For my little 18,000 lb coach, here is what I observe on a 80 degree day on asphalt (all tires set at 85 psi cold) - fronts 16 psi rise in the fronts + 2 psi more in the full sun - rear outside 22 psi rise + 2 degrees in the sun - rear inside 24 psi rise in pressure - all this at 60 mph on a flat Texas Interstate. If you don't like the tire pressure rise amount, add more tire pressure to a cold tire, BUT never exceed the max rated tire pressure on the sidewall (cold tire). - Or you could slow down or reduce weight.
Now I will step down from my soap box.... Next!

Why would climbing a grade result in more tire flex? The contact patch doesn’t change and the speed typically decreases.

[Beau388]

Climbing a grade transfers some the weigh on the front tires to the rear increasing the size of the tire patch. Also, tire scrub is increased because in the increased power transferred to the tires.

[Pete'sMH]

Originally Posted by Beau388

Climbing a grade transfers some the weigh on the front tires to the rear increasing the size of the tire patch. Also, tire scrub is increased because in the increased power transferred to the tires.

Oh. Thank you.